But last night - to coincide with the birthday of David Attenborough - he created a surprise new piece on the side of the Pilgrims Hospice charity shop in the town centre.

'Wasted Time'. Pic: Catman (9947462)

The new artwork - entitled Wasted Time - depicts an hourglass.

But instead of sand, it contains a map of the world - which appears to turn into plastic bottles as it trickles down, falling into a large heap below.

"I wanted to do it as close to the sea as I could..." Catman

Speaking exclusively to KentOnline, the notoriously private artist said: "The piece is playing on the fact that we're running out of time to do something about what we're doing to the planet - creating plastic pollution that's going into the water.

"It's also portraying the way we're turning the earth's natural minerals into this man-made human substance that's slowly killing the earth."